Bug in mult method fixed.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4483 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/bigdecimal/bigdecimal.c

@@ -858,7 +858,7 @@ BigDecimal_mult2(VALUE self, VALUE b, VALUE n)
     ENTER(2);
     Real *cv;
     U_LONG mx = (U_LONG)GetPositiveInt(n);
-    if(mx==0) BigDecimal_mult(self,b);
+    if(mx==0) return BigDecimal_mult(self,b);
     else {
        U_LONG pl = VpSetPrecLimit(0);
        VALUE   c = BigDecimal_mult(self,b);